The National Taxpayers Union (NTU) and a host of other conservative groups in Washington urged congressional Republicans to stand firm on sequester spending cuts as they debate funding for the next fiscal year.

“If Congress reneges on promises to restrain spending just two years after the passage of discretionary spending caps, it would send a powerful message to the American people: Congress cannot control its profligate spending,” the NTU wrote in an open letter to Republican leadership Friday.

“This could, in turn, jeopardize other important conservative priorities, as well as the prospect for economic prosperity,” the letter continues. “Thus, we believe maintaining post-sequester [Budget Control Act] caps should be of the utmost importance.”

Part of a 2011 grand bargain between President Obama and Republicans over raising the debt ceiling, the sequester slightly reduces the rate at which baseline federal spending is increasing. Sequester reductions kicked in this March and mandate a $1.2 trillion reduction in projected across-the-board federal spending, spread out over nine years. (While projected spending hikes will be slightly lower, spending will still increase in every quarter.)

Sequester treatment has already saved taxpayers $85 billion, and cuts to 2014 spending increases are projected to total $109 billion.

But President Obama and congressional Democrats are trying to scuttle the sequester piece-by-piece before January cuts kick in, and conservative groups are worried some Republicans may join them.

“I think the sequester is very much in jeopardy, certainly from the left but there’s also a lot of people on the right — the more hawkish communities — looking for ways to avoid reducing military spending” said Brandon Arnold, vice president of governmental affairs at NTU, in an interview with The Daily Caller News Foundation.

The sequester shaved $37 billion in increased spending from the Pentagon’s budget last year, with a further $52 billion projected for 2014. Generals, defense experts and Republican hawks have all blasted the cuts.

Nearly every Republican on the House Armed Services panel signed a letter to Republican Budget Chairman Paul Ryan, demanding that defense sequester cuts be reversed. “The concern of a hollowing of the force is very real; indeed, the readiness of our forces has already eroded,” they wrote.

And the Wall Street Journal reports that top Republican leaders, including House Speaker John Boehner, recently told the White House they are willing to torpedo the sequester in exchange for a long-term budget deal.

“I can understand that to some extent,” said Arnold. “There’s certainly some things out there that would be worth trading for. But for the most part, I think this is the law of the land, and we should put this issue to rest and move on to other avenues to reduce debt.”

Arnold thinks its important conservative groups remain united in their push to preserve the sequester. “There’s been a problem in the conservative movement over the past several months, with a lot of different groups on a lot of different pages in terms of what they want,” he said, singling out tax reform and the repeal of Obamacare.

“I think it’s important for conservative groups to step up and show folks on the Hill just how important [the sequester] is,” he concluded

Eighteen organizations signed the letter to Republican leadership, including Americans for Tax Reform, Generation Opportunity, the Competitive Enterprise Institute and the Coalition to Reduce Spending.

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